The present invention is directed to a machine constructed to process plates or sheet workpieces into blanks for being converted into a package. The machine includes an infeed station, at least a press station for cutting, creasing or embossing, which press station includes an upper fixed beam or platen, a lower movable beam or platen and means for moving the lower movable beam or platen toward and away from the upper beam, a conveyor, which is formed by a pair of close-looped chain provided with gripper bars, is arranged to carry the sheet from one processing station to another and between the two platens and an arrangement or means for removing the front waste from the sheet, which is situated on an upper return track of the chain pairs.
In the prior art there exists a machine for processing which has an upper beam for processing or cutting a sheet into a blank, an arrangement for removing the waste of the blank, followed by means for removing the front waste from the gripper bars. As illustrated in FIG. 1, which is taken on the operator's side of the machine, the machine has an infeed station I, in which is located a pile Pe of sheets F; a cutting, creasing and/or embossing station P in which the lowermost sheet F of the pile Pe is carried between an upper fixed beam or platen Ss and a lower, movable beam or platen Si of the press; a stripper station E in which the offale De, which is cut out of the sheet F by the cutting device fitted on a tool O itself held on the upper beam Ss of the press P, are separated from the sheet F and ejected downward into a waste collector D; a delivery station R in which the blanked sheets are assembled on a conveyor system T to build up in a pile Ps, which, when completed, is carried out of the machine.
In the course of the operation of the above-described machine, the sheets F are carried individually from one station to another by means of a gripper bar system B, which is moved by a pair of chains C which form a closed-loop circuit having a lower run passing between the platens Ss and Si, through the stripper station E, the delivery station R and then a return upper run. To this aim, the lengthwise ends of the machine are foreseen to be equipped with two return devices Rm and Ra, with the device Rm illustrated as being a pulley or roller for the chain pair C. The first return device Rm is situated on the entrance between the infeed station I and the press P with regard to the lower run so that the lower run of the path for the chains and bars B will pass between the upper beam Ss and the lower beam Si. The second return device Ra is situated downstream of the stripping station E. A leading edge of the lowermost sheet F1 of the infeed pile Pe is seized in the infeed station I by an opened gripper bar B1 owing to a gripper opening device (not represented). In such a machine, the sheets are generally processed in line with the principle called an "operation with front waste", which is to say that every sheet F is blanked in the cutting station P in such a way that part of the whole of its front or leading edge will be waste Df, which is then to be separated from the sheet. However, the separation of the front waste Df within the stripper station E is not possible, since the very leading edge or front waste is and will have to remain held by the gripper bar B in order to enable the sheet F to be transferred to the delivery station R.
Generally, such a machine is not used individually, but is part of a line of various machines with a length frequently involving space problems on account of its encumbrance, the means to be used for removing the front waste Df from the gripper bar B and carrying it out of the machine have, up to now, been arranged above the delivery station R in the area where the gripper bar B returns in a downstream direction. To this aim, the machine is to equipped in that area with an opening device of the gripper bar B and a device which will push the front waste Df out of the gripper bar B, a carrier belt Tr which collects the dropped waste Df and carries it out of the machine toward the side opposite the side at which the operator is situated.
Generally, the carrier belt Tr is driven by an electric motor which differs from the main motor, since nothing requires full synchronization of its movement with the one of the other items built into the various operating stations, such as P, E and R described above. This, though, is not the case regarding the opening device of the gripper B, which device is foreseen in the area where the front waste Df is to be removed from the gripper bar B. Such an opening device of the gripper bar B comprises at least a component shiftable between a first position in which it is located outside the space attributed to the passage of the gripper bar B and a second position which, with the gripper bar B at rest, is to be occupied inside of said passage in order to act on one of the components of the gripper bar B so as to open them. Conspicuously, such an opening device of the gripper bar B is to be perfectly synchronized with the successive alternate moves of the chain pairs C carrying the gripper bar B and, hence, the sheet F from one processing station to the other. Up to now, such a synchronizing effect is obtained by having the opening device of the gripper bar B driven directly by the main motor of the machine, for example a motor which is to ensure the drive of the lower movable beam Si by means of a drive worm and an assembly of connecting rods and crankshafts K, as well as the drive pulley of the chain pair C to be added to the entrance end of the return device Rm. To this aim, a chain G is to connect, for instance, a drive pulley of the gripper opening device to another situated in the inlet return device Rm, which chain is illustrated in dash lines in FIG. 1 and is usually located on a side of the machine opposite the side on which the operator is positioned. As can be gathered from FIG. 1, the chain G is to extend over a large distance, which is still to be lengthened by the fact that its track is not even, since it has both a horizontal section and a vertical section so that both the accessibility and visibility of the various operating stations will not be interfered with. However, on account of the present exacting marketing requirements, which demand an increasingly high production speed, serious operating problems might be incurred by a chain of a particular length. In fact, the linear travelling speed of the chain can be very high, it the opening control of the gripper bar B is to be achieved. Conspicuously, a chain operated in such a condition is likely to cause trouble, due to breakage of the components, noise, vibrations, and other problems with long chains. Additional attention is to be drawn to the fact that it is most inappropriate having to use a chain of such a length acting jointly with numerous items, as well as with guiding pulleys for achieving the operation, such as opening the gripper B, which opening action is finally disproportionate with regard to the whole of the machine with the means put to operation for its achievement.
In addition, placing the belt carrier Tr in the upper part of the delivery station R prevents easy access to and sufficient visibility of this station, especially on the side opposite the operator, i.e., the rear or lower areas of the outlet end of the carrier belt Tr, where sliding rails are generally located for guiding the front waste Df toward the waste collector D at the bottom of the stripper station E. Lacking visibility and accessibility, as well as insufficient space, will be particularly undesirable if the delivery station R insures the joint operation of the so-called blank separation by means of two movable frames, of which one is situated underneath and one above the chain pairs C. In addition, in machines with relatively simplified delivery stations R and for which accessibility and visibility above the chain pair C is not a real requirement, the removal of the front waste Df in that very area will cause the machine to be considerably lengthened for the accomplishment of an operation which, as already stated, is nonetheless of secondary importance. The same conclusion will result also with a machine comprising only two operating stations, for example an infeed station I and a cutting or processing station P provided with the press. In such a case, it will be obvious in comparison with the case illustrated in FIG. 1, that sufficient space is to be made available between the upper beam Ss of the press and the downstream return device Ra of the chain pair C exclusively for the purpose of achieving the removal of the front waste Df.
The above considerations according to which the cutting station can be combined either only with the delivery station, and of course also with the infeed station, or with a stripping station E and the delivery station R show, moreover, that the far-reaching modifications of the engineering are to be envisioned for determining the individual adaptation of the position of the carrier belt Tr and of other components destined to insure the removal of the front waste Df.